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H. L. TANNER. I DAMPING MEANS FOR GYROSCOHC PENDULUMS.

APPLICATION FILED JUNE 8,1917.

Patented Dec. 9, 1919.

4 SHEETSSHEE1 l.

Tl I]! INVENTOR I HARRY L .TANNER.

. BY Mmfij H. L. TANNER.

DAMPING MEANS FOR GYROSCOPIC PENDULUMS.

APPLlCATlON FILED JUNE 8. I917.

Patented Dec. 9, 1919.

4 SHEETS-SHEET 4.

I I 3 1 M,-

I II'NVENTOR I /ARRYL .T4NNER.

llll'llll UNITED STATES PATENT OFFICE.

HARRY L. TANNER, OF BROOKLYN, NEW YORK, .ASSIGNOR TO SPERRY GYROSCOPE COMPANY, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

Speoiflcation of. Letters Patent.

Patented Dec. 9, 1919.

. Application filed June 8, 1917. Serial No. 173,557.

To all whom it may concern;

Be it known that I, HARRY L. TANNER, a citizen of the United States of America, residing at 1144 East 19th street, Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Damping Means for Gyroscopic Pendulums, of. which the following is a specification.

This invention relates to gyroscopes adapted to be used for stabilizing purposes on aeroplanes or other moving vehicles. More particularly it relates to a gyroscopic pendulum of long period adapted to malntain a reference. plane or planes for controlling an aeroplane or for observation purposes. The invention is independent, however, of the type of pendulum em loyed whether there be one or a plurality o gyro scopes used.

It is now recognized that. by making the period of the gyroscopic pendulum suiliciently long, the permanent effect of acceleration pressures and the like can be largely eliminated. It has been found, however, that small oscillations of the gyro-pendulum will arise which,if not suppressed by specialdamping means give rise to trouble. Friction about the axes of oscillation, I have discovered, and all ordinary damplng devices are unsuited for this purpose, since it is found that friction about the principal axes of support will increase the oscillations of the pendulum if the aeroplane is turning in the opposite direction from which the rotor of the gyroscope is turning, although it will damp if the aeroplane is turned in the same direction.

The main object of this invention is to provide means for quickly and effectively damping out or suppressing oscillations of the pendulum under all conditions without effecting the accuracy of the settling point or causmg other disturbances.

Referring to the drawing in which what I now consider to be the preferred form of my invention is shown,

Figure 1 is a plan view of one form of gyroscopic pendulum with my invention applied thereto.

Fig. 2 is a side elevation thereof.

Fig.3 is a front or rear elevation. Fig. 4 is an enlarged detail of the dampmg means I prefer to employ.

Fig. 5 is a side elevation of a modified form of damping means.

Fig. 6 is a wiring diagram thereof.

Fig. 7 is a.front elevation of the third modification, in which a plurality of gyroscopes are employed.

. Fig. 8 is a corresponding view of the fourth modification.

Fig. 9 is a detail of the contacts employed in connection with Fig. 7.

10 is a corresponding detail of'Fig. 8.

Fig. 11 is a diagram representing a complete oscillation of the pendulum showing the points at which the damping means are applied in all forms of the invention.

Fig. 12 is a detail of a portion of Fig. 8.

Fig. 13 is a diagram illustratin the ac tion of the modification shown in ig. 8.

In the Figs. 1 to 6, I have shown but a single gyroscope 1 comprising a rotor casing 7 within which the rotor is journaled on a vertical spinning axis and which is pivotally mounted on axis 8, 9 within gim- 'bal ring 10, the said ring being in turn. supported on axis 2, 3 in brackets 4 and 5 on base plate 6. The gyroscope is centralized by the yielding force of gravity aboutboth horizontal axes. A swinging loop or bail 11 is ivoted about axis 12, 13 in brackets 14 and 15 preferably normally in line with axis 8, 9. The said loop is made with a depression or track' 16 in which engages a roller 16 secured to the bottom of the rotor casing 7. Contacts 18, 19' and 20, 21

may be provided to operate the control of the aeroplane about both axes, the contacts '18 and 20 being mounted on gimbal ring 10 and loop 11, respectively; while contacts 19 and 21 are relatively fixed with respect to the gyroscope. In order that the device may be also used as an inclinometer I have shown indicating scales and pointers 50 and 51 mounted thereon.

In order to damp the oscillations of the gyroscope, I provide means for compelling the gyroscope to do work as it oscillates.

.in altered in the In the form shown this may be accomplished by applying a torque on the gyroscope opposed to the direction of its oscillation so that the oscillationmust work against the said torque. Preferabl' the same source of torque is made use of or this purpose as is.

used to centralize'the gyroscope, e. g., gravity, the action or strength of the torque bedifierent phases of an oscillation so that said torque is greater when opposing an oscillation than when accelerating it. My preferred methodof applying such a torque is to shift the relative positions of the center of gravity of the gyropendulum and the center of one or both of the axes of support so that as the gyroscope precesses or oscillates the center of gravity will be shifted in a direction to cause theaction of gravity to oppose said precession.

One method of shifting the center of gravity is to provide the gimbal ring 10 with a bracket 22 on which is mounted electro-magnetic means such as a pair of electro-magnets 23 and 24. Pivoted or otherwise movably connected to the said bracket is anarm 25, shown as pinned to, the bracket at 26. Said arm is also jou'rnaled on the pivot pin 27 extending from bracket 5 by means of an anti-friction bearing 28. Extending from each side of the said bearing are rods 29, 30 having enlarged ends 31 which are mounted in the bracket 22. Contralizing compression springs 33 fixed be tween collars 3a on shafts 29 and 30 and washers 60 loosely mounted thereon may be provided to maintain the bearing in the central position with the arm 25 midway between the magnets 'as' shown in Fig. 3. In this position of the parts the gimbal ring 10 and hence the entire gyro-pendulum will be in line with the axis 2, 3 and perfectly balanced. But when magnet 2a (for instance) is excited arm 25 actin as the armature of said magnet will be rawn over to the position shown in Fig. 4. Since pin 27 is fixed this will result in pushing the entire gimbal ring 10 to the left and hence cause gravity to exert a downwardly directed force on the left hand side of the gyro-pendulum. If the pendulum at that time is oscillating in a clockwise direction, Figs. 3 and 4, it will readily be seen that the force of gravity opposing such movement will readily damp it out.

In order to control the application of said damping means, I prefer to employ contacts or the like brought into operation by the inclination of the gyroscope about one or the other of the horizontal axes. It is important for my purposes, however, that the center of gravity be shifted in such direction and at such a time as will cause the existing oscillatory movement to be opposed by gravity, avoiding at the same time aiding the oscillation by gravity during another phase of the oscillation- I have found that 'to secure the maximum damping effect, the

force of gravity should be brought into operation approximately one quarter of a period of -'0S0illati0n' after the said oscillation, or in other words, it should lag a quarter phase behind the oscillatory movement.

employin contacts about the axis on which the damping means is placed and inserting between said contacts and the damplng One method of accomplishing this result is by,

means a time-lag device. This method .is

other axis. In this instance, the contacts are brought into operationby'the inclination of the gyroscope about an axis at right angles to the axis of damping, or in the em odiment shown in Figs. 1 to 4 about axis 8, 91 For this purpose,-I secureto the loop 11 a contact 36 adapted to cotiperatewith independently mounted contact sectors 37 and 38 so as to excite one or the other of electromagnets 23 or 24 depending on the position of the brush 36 (see Fig. 1). I prefer to mount the contacts 37 and 38 on an independently mounted pendulum, or

pendulous device 39 pivoted about an axis. 40 substantially in line with or parallel to axis 12, 13-.

I prefer to mount the apparatus on the aeroplane in the position represented by the arrows A and B in Figs. 1 and 2 which represent the direction of flight of the aeroplane, since in this position the auxiliary pendulum 39 is unaffected by centrifugal forces due to the turning of the aeroplane, while the pressures due to stopping and starting are of comparatively short dura tion.

The operation'of the preferred form of my invention will be best understood by reference to Fig. 11. In this figure, the curve A represents a complete oscillation of the gyro pendulum about axis 8, .9, while curve B represents the oscillatory movements of the gyro pendulum during the same time about axis 2, 3.

Starting at the point 0 in the curve A which represents the gyro passing through its horizontal position about axis 8, 9, it Wlll be seen that as soon as point 0 is passed, contact 36 will be brought into contact with sector 37, for instance, thereby bringing into operation the damping means about axis 2, 3.

The point 0 oncurve A, it will be seen, corresponds to point P, on curve B, which is the point of maximum, inclination about other words, will have to climb up, hill. It

clock-wise.

imilar y, while the roscope is moving about axis 8, 9, from point C,'back to point C, which it will be understood corresponds to point "O, the ;damping-means has been.-

placed in operation-in the opposite direction to oppose the movement aboutaxis 2, 3 from point P to P". Speaking concretely, with the gyroscope revolving in the direction of the arrow shown in Fig. 1, andthe gyroscope 1nclined about axis 8, 9 so that the top side is raised out ofi the plane of the paper, the resulting. precession about axis 2, would be in the direction to cause the rismg of the right hand side of ring 10. In Fig. 3 this movement would be countermagnet 23 is placed in circuitwithcontact 38 by-the contact therewith of brush 36, so that the center of gravity of the apparatus is shifted to the right. The gyroscope in processing, therefore, will have to continually oppose this gravitational torque; or in will readily be seen that this means will quickly damp out any oscillations.

As abovestated, the damping-torque may be brought into operation by contacts about the axis of damping, if desired, as shown in Figs. 5 and 6. These figures alsoillustrate that the damping means maybe employed about both axes, if desired, and in addition a modified form of dampen In Fig. 5, which corresponds to Fig. 2, the pendulum 39 and similar parts will be at once recognized. Contacts 36, 37 and 38 indirectly control electromagnets 23 and 24: mounted preferably on gimbal ring 10.. An armature 60-is pivoted at 61 on a bracket 62on said ring so as to be attracted by said magnets, and carries a ball or other mass 63. The armature is normally held vertical by centralizing springs 64:, 65,- but excitation of one or the other .of magnets 23' or 24 will throw it to the right or left and hence shift the center of gravity of the system. In order to introduce the proper time lag between the contacts and the magnets, I may employ a solenoid 66 having a pair of windings 6 and 68 in circuit respectively with contacts 37 and- 38. Themov-able core 69 of said solenoidis normally held midway between said windings by-springs 70 and 71, Said' To oppose this movement the core has secured thereto a brush or trolley 72 adapted to contact with strips 73 and 74 spaced by a block of insulation 75. A dash pct. 76 or other retarding device is also provided, the piston 77 thereof being secured to said core. Contacts 73 and 74 are placed in circuit with magnets 23 and 24 respectively. The dash pot is preferably so designed that trolley 72 does not contact with strip 73, for instance, until approximately a quarter of a period after contact of 36 with 38 so that the center of gravity will not be shifted until the gyroscope reaches its extreme position of elevation. A similar damping system is also shown about axis 2, 3 comprising pendulum 39, contacts 36', 37' and 38, magnets 23" and 24:, inverted pendulum 63, solenoid 66' and contacts 7 2 7 3 and 74. In this connection I may provide means whereby pendulum 39 and its associated contacts and solenoid may be eliminated and magnets 23" and 24" controlled directly from the contacts 72', 73

and 74', the characteristics of the gyro-pendulum being relied upon to impart the necessary time lag without the use of a dashpot. A doublethrow switch readily accomplishes this pur ose, as shown in Fig. 6.

The operation 0 this modification will be readily understood by reference to curve A of Fig. 11. Contact will be made between brush'36 and sector 37 as soon as point 0 is passed through. The damping means will not be brought into operation, however, until the point H is reached, which is a quarter period behind point 0. Upon being placed in operation, the dampin means will remain effective, until point is reached, even though point C is passed through, due to the action of the dashpot. At or near point H, however, the actual damping means will be reversed due to the continued contact of brush 36 with sector 38 so that the oscillation of the pendulum on rising will be opposed throughout the period of rise.

It will, of course, beunderstood that the application of the damping means need not be spaced exactly a quarter phase behind the oscillation to be suppressed since other relationships will produce damping. It is to noted, however, that if another relation of the parts is employed, say for instance, if the damping means is brought into operation an eighth of a period behind the oscillation to be suppressed, that said damping means will be effective approximately only one half thetime, since during the other half whatever damping efiect could be obtained when the oscillation was in one direction would between point H and point D would be substantially offset by acceleration of the oscillation between points D and H, point D being in line with point D.

As is readily apparent, the application of my invention is, of course, not limited to gyroscopic pendulums employing a single gyroscope. In Figs. 7, 8, 9 and 10, I have shown my invention as applied to a gyroscopic pendulum Containing a plurality of gyroscopes. In these figures the mam frame 100 is supported for oscillation about axes 2', 3, while a pair of gyroscopes 101, 102, are pivotally mounted withln sald frame on vertical axes 103, 104, the spinning axes of the gyroscopes being indicated at 180, 131. The gyroscopes are normally spun 1n opposits directions and are coupled for equal and opposite precession or oscillation within the frame by means of gears 105, 106. The gyroscopes are normally centralized by yielding spring 107, stretching between lugs 108, 109 on the gyro casings; a spring being employed to furnish a yielding centralizing force instead of gravity in this instance.

Secured to gyroscope 101 is a contact arm 110, preferably in the form of a leaf spring (Fig. 9). Said arm is adapted to be brought into engagement with either one or the other of contacts 111 or 112, secured to frame 100 and also preferably in the form of springs. Said contacts are placed in circuit with a means for applying a torque about the axes of support of frame 100. In this instance,the means is shown as a device 22 similar in construction to device 22 in the form of the invention shown in Figs. 1, 2 and 3. It is readily apparent that the contact of 110 with either 111 or 112 will be maintained as long as the gyroscope is not in its central position and thus operate the torque applying device in substantially the same manner as described in Fig. 1.

In Fig. 8 aslightly different method ofapplying the damping torque is shown. In this figure, the centralizing spring 107 may extend between point 108 on gyro 101 and a point 109 on a movable block 113 on the main frame. (see Fig. 12). A pair of solenoids 114 and 115, having their cores 117 connected to the block may be positioned on either side thereof, the block being normally centralized by springs 116 acting on the cores of the solenoids; It will readily be seen that if solenoid 114:, for instance, is on ergized, that the block 113 will be drawn to the left of Fig. 12, and hence change somewhat the direction of the force applied thereby. By controlling the action of the solenoids, the block may be drawn in such a direction as to cause an increase in the tension of spring and the torque applied thereby when the gyroscope is moving against the tension of the spring (2'. e. from 0 to H or C to H in Figs. 11 and 13) and to decrease such tension when the gyroscope moves in an opposite direction (2'. e. from H to O). For this purpose. the solenoids are connected in circuit with contacts 110, 111 and 112, the contact 110'- being connected to the gyro 101, while th latter two contacts are on the frame 100. The contacts are preferably fairly rigid in construction in contrast to contacts 110 to 112, but contact 110 is loosely clamped on the vertical shaft 120 supportinggyro 101 so that as soon as it strikes either of the other contacts, it will slip on said shaft. It will readily be seen that with this arrangement as soon as the gyroscope changes its direction of oscillation (at H and H) contact 110 will be moved immediately away from the contact with which it was in engagement to the other contact. This will innuediately change the direction of application offorce by the spring.

The complete action of this form ,of the invention may be best understood by reference to the diagrams in Figs. 11 and 13.- In the latter figure curve H C H represents the path of movement, of the point 108 on the gyro, where the spring 107 is attached thereto, while line X Y Z represents the path of the point 109 of attachment of the spring to block 113. As point H is passed through, the block is drawn backwardly so that 109' is moved to X. This will at once shorten the spring as will be evident on comparing line H X with H Y or H Z, thereby reducing the accelerating action of the spring as the gyro moves from H to C. As the gyro moves on from G to H, however, the spring will be stretched more than if the point 109 were at Y or Z, as will be evident from comparing lines H X, H Y and H Z, thereby causing a greater force to oppose said motion than aided it from H to C.

Another important effect will be to change, temporarily, the centralized position of the gyroscope from C to 00 (Km being parallel to O Y) so that the spring will onpose the movement of the gyro from a: to

H which is greater than the distance from H to ea. As point H is passed through 109 is moved from X to Z and a reverse action takes place.

In accordance with the provisions of the patent statutes, I have herein described the principle of operation of my invention, together with the apparatus, which I now. consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted and some of the features of each modification may be embodied in the others, without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent 1s: v

1. In combination, a pendulum, means for shifting the point of support of said pendulum and means responsive to oscillation of said pendulum for controlling said first named means.

2. In combination, a pendulum, means for shifting the relative position of the centers of gravity and support of said pendulum and means responsive to oscillation of said pendulum for controlling said first named means.

3. In a gyro-pendulum, means for shifting the relative position of the centers of gravity and support for damping the oscilations thereof.

4. In a yro-pendulum, means for shifting the re ative position of the centers of gravity and support for damping the oscillations thereof, and controlling means therefor adapted to effect action of said damping means out of phase relation with the oscillations of the pendulum.

5. In a gyro pendulum, a pendulously mounted support, a gyroscope mounted thereon for oscillation with respect thereto, yielding means operable thereon for centralizing the gyroscope within the frame, and means for altering the action of said yielding means during different phases of an oscillation.

6. In a gyroscopic device, the combination with a gyroscope, of yielding means permitting oscillation thereof but causing it normally to remain in a position of equilibrium, and means for altering the action of said means whereby the position of equilibrium is changed.

7 In a gyroscopic device, the combination with a gyroscope, of yielding means permitting oscillation thereof but causing it normally to remain in a position of equilibrium, and means for altering the action of said means during different phases of an oscillation.

8. In a gyroscopic device, the combination with a gyroscope, of yielding means permitting oscillation thereof but causing it normally to remain in a position of equilibrium, means for altering the action of said means during difierent phases of an oscillation, and means responsive to such oscillations for governing the action of said altering means.

9. In a gyro pendulum, a pendulously mounted support, a gyroscope mounted thereon for oscillation with respect thereto, yielding means operable thereon for centralizing the gyroscope within the frame, means for altering the action of said yielding means, and governing means therefor adapted to bring said altering means into operatlon when the direction of oscillation changes.

10. In combination, a plurality of pendulums of different periods and means controlled by one of said pendulums for shifting the relative position of the centers of gravity and support of another of said pendulums.

11. In combination, a pair of pendulums of different periods and means controlled by relative movement of said pendulums for shifting the relative position of the centers of gravity and support of one of said pendulums.

12. Ina gyroscopic stabilizing device, for aeroplanes and the like, a gyroscopic member pendulously mounted about both horizontal axes and means for shifting the relative position of the centers of gravity and support about an axis responsive to an inclina tion of said member about the other axis.

13. In a gyroscopic pendulum, a gyroscopic member pendulously mounted about both horizontal axes, means for causing a torque. to be applied about one of said axes,

an independently --mounted pendulous device pivoted about an axis substantially parallel to the other of said axes, and governing means for said other means actuated by the relative movement between said device and said member about the last named axis.

14. The combination with a gyroscopic pendulous member of an independent pendulum mounted adjacent thereto, coiiperating contacts mounted on said pendulum and member, and a damping means for said member brought into operation by said contacts.

15. In a gyroscope, means for shifting the relative'position of the centers of gravity and support, comprising a support, a bearing member journaled thereon, a gyroscopic device connected with said member and movable laterally with respect thereto and means for shifting said device with respect to said member.

16. In a gyroscope, means for shifting the relative position of the centers of gravity and support, comprising a support, a bearing member journaled thereon, a gyroscopic device connected with said member and movable laterally with respect thereto, yieldi means for maintaining said member and sai device in a predetermined position, and means for shifting said device with respect to said member.

17. In a gyro-pendulum, means for shifting the relative position of the centers of gravity and support, comprising a support, a bearing member journaled thereon,

gyroscopio device pivoted to said member and electro-magnetio means for rocking said device on said member.

18. In combination, a gyroscopic pendulum and means comprlsing an independently mounted auxiliary pendulum for damping oscillationsof said gyroscopic pendulum.

19. In combination a gyroscopic pendulum, an independently mounted pendulum and means operable on relative movement of said pendulums for damping oscillations of one of said pendulums.

20. In combination,a pendulum and roscopically controlled means for causmg a gravitational torque to be applied to said pendulum.

21. In combination, a pendulum and gyroscopically controlled electro-magnetic means for causing a gravitational torque to be applied to said endulum.

22. In com ination, a gyroscopically stabilized pendulum, means for shifting the point of support of said pendulum and means responsive to oscillation of said pendulum 'for controlling said first named means.

23. In combination, a roscopic device pivoted about a horizontal axis, means for shifting the relative position of the centers of gravity and support of said device and means responsive to oscillation of said device for controlling said first named means.

In testimony whereof I have aflixed my signature.

HARRY L. TANNER. 

